| The claw pole is one of the key components of the vehicle claw pole generator,and its magnetic properties directly determine the power generation performance of the automobile generator.Forming process has been the main method for the production of claw pole,while the forming process has significant effect on the magnetic properties of claw pole forgings.In order to provide support for the magnetic property oriented optimal design for the claw pole,the resarch on the prediction of magnetic property of forgings were carried out in this study.The low carbon soft magnetic material is taken as the research object,and the prediction model of magnetic flux induction related to strain and temperature was constructed.By inserting the prediction model into FEM simulation software,the prediction of the magnetic propertie distribution of the forged claw pole was realized,thus it could provide theoretical guidance for the selection of claw pole forging process and provide reference for the structural design of claw pole components.In order to realize the accurate numerical simulation of the hot forging process of claw pole,a sinusoidal flow stress model was proposed based on the flow stress behavior of the soft magnetic material in a large strain range under different heat deformation temperatures and strain rates.Compared with the classical flow stress model,the proposed model can describe two different softening mechanisms of materials and can meet the requirements of flow stress curve extrapolation under the condition of large strain.Besides,it has good accuracy and implantability in FEM simulation.In order to study the influence of thermal deformation on the magnetic properties of soft magnetic materials,a testing platform for the direct current magnetic properties of soft magnetic materials was established to test and analyze the changes of magnetic properties such as magnetic flux induction,coercivity and remanence under different process parameters.According to the influence law of thermal deformation on the magnetic properties of soft magnetic materials,based on the magnetic-mechanical coupling theory of magnetic materials,considering the effects of plastic strain and dynamic recrystallization on the micro magnetic domain structure of soft magnetic materials,a new prediction model of magnetic flux induction related strain and temperature was put forward.The key parameters of the model were determined based on the experimental data,and the reliability of the model was verified.The flow stress model in the form of sinusoidal function and the prediction model of magnetic flux induction related to strain and temperature were inserted into the FEM simulation software through secondary development.Thus,a thermal-mechanical-magnetic flux induction coupling finite element simulation scheme was construced which is suitable for thermal deformation of soft magnetic materials for claw pole,and the prediction of magnetic flux induction distribution of typical claw pole forgings was realized.It lays a necessary foundation for the structural design and manufacturing process optimization of the claw pole parts. |
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